Glossary

A:An A horizon is a mineral horizon meaning it contains ≤ 17% organic C (about 30% organic matter) by weight. It forms at or near the surface in the zone of leaching or eluviation of materials in solution or suspension, or of maximum in situ accumulation of organic matter or both.

AB or BA:A transitional layer than shows characteristics of both A and B horizons. The dominant horizon is listed first.

ABgj:An AB horizon characterized by faint to distinct mottling within 50 cm of the soil surface. The A horizon features are dominant over B horizon features.

Ae:An A horizon characterized by the eluviation of clay, Fe, Al, or organic matter alone or in combination. When dry, it is usually lighter colored (higher in color value by one or more units) than an underlying B horizon.

Aeg:An A horizon characterized by the eluviation of clay, Fe, Al, or organic matter alone or in combination. It has dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction.

Aegj:An A horizon dominantly characterized by the eluviation of clay, Fe, Al, or organic matter alone or in combination. When dry, it is usually lighter colored (higher in color value by one or more units) than an underlying B horizon. Secondary features include the presence of faint to distinct mottles within 50 cm of the soil surface.

Aej:It denotes an eluvial horizon that is thin, discontinuous, or slightly discernible. When dry, it is usually lighter colored (higher in color value by one or more units) than an underlying B horizon.

Aeu:An A horizon dominantly affected by eluviation and physical or faunal processes. It is characterized by the eluviation of clay, Fe, Al, or organic matter alone or in combination. When dry, it is usually lighter colored (higher in color value by one or more units) than an underlying B horizon. Disruption due to physical and faunal activities includes tree blowdowns, mass movement of soil on slopes, and burrowing animals (particularly earthworms).

Ah:An A horizon enriched with organic matter, that is darker (has a color value at least one unit lower than the original parent material) and/or has 0.5% more organic C than IC. It contains ≤ 17% organic C by weight. Some Ah horizons satisfy the criterion for "f" but are not designated this suffix.

Ahb:A buried A horizon enriched with organic matter that is darker (has a color value at least one unit lower than the original parent material) and/or has 0.5% more organic C than IC. Burial may occur by mass wasting of soil downslope, intermittent flooding or deposition of air-borne material.

Ahe:This A horizon is enriched with organic matter that is darker (has a color value at least one unit lower than the original parent material) and/or has 0.5% more organic C than IC. It has also undergone eluviation of clay, Fe, Al and/or organic matter as evidenced, under natural conditions, by streaks and splotches of different shades of gray and often by platy structure.

Ahgy:An A horizon dominantly affected by surface vegetation, frequent saturation and cold temperatures. Therefore, it is enriched with organic matter that is darker (has a color value at least one unit lower than the original parent material) and/or has 0.5% more organic C than IC. It has dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. And it is affected by cryoturbation, made apparent by a disrupted and broken horizon, incorporation of materials from other horizons, and mechanical sorting in at least half the pedon.

Ahk:An A horizon enriched with organic matter that is darker (has a color value at least one unit lower than the original parent material) and/or has 0.5% more organic C than IC. It also has visible effervescence when dilute HCl is added indicating the presence of calcium carbonate.

Ahu:This A horizon is enriched with organic matter that is darker (has a color value at least one unit lower than the original parent material) and/or has 0.5% more organic C than IC. It is also disrupted by physical or faunal processes, including tree blowdowns, mass movement of soil downslope and burrowing animals (especially earthworms). Evidence of disruption must be present in at least half the cross section of the pedon.

Ahy:An A horizon enriched with organic matter that is darker (has a color value at least one unit lower than the original parent material) and/or has 0.5% more organic C than the original parent material. It is also affected by cryoturbation as manifested by a disrupted and broken horizon, incorporation of materials from other horizons, and mechanical sorting in at least half of the pedon.

Ahz:A frozen A horizon which is enriched with organic matter that is darker (has a color value of at least one unit lower than the original parent material) and/or has 0.5% more organic C than the original parent material.

Angular blocky:The faces of aggregates are rectangular and flattened, and the vertices are sharply angular.

Ap:An A horizon that has been disturbed by human activity such as mixing of the upper soil by ploughing in agricultural landscapes. Some Ap horizons satisfy the criterion for "f" but are never designated this suffix.

Apk:An A horizon that has been disturbed by human activity such as mixing of the upper soil by ploughing in agricultural landscapes. It also has visible effervescence when dilute HCl is added indicating the presence of calcium carbonate.

Ay:An A horizon affected by cryoturbation as manifested by a disrupted and broken horizon, incorporation of materials from other horizons, and mechanical sorting in at least half of the pedon.

B:A B horizon is a mineral horizon meaning it contains ≤ 17% organic C (about 30% organic matter) by weight. It is characterized by enrichment in organic matter, sesquioxides, or clay; or by the development of soil structure; or by a change of color denoting hydrolysis, reduction, or oxidation.

BC or CB:A transitional layer than shows characteristics of both B and C horizons. The dominant horizon is listed first.

BCc:An irreversibly, strongly cemented BC horizon denoted as Duric which usually has an abrupt upper boundary to an overlying podzolic B horizon and a diffuse lower boundary at least 50 cm below. Cementation is usually strongest near the upper boundary which occurs commonly at a depth of 40-80 cm from the soil surface. Color varies little from the parent material and the structure is usually massive or very coarse platy.

BCgj:A BC horizon where B horizon characteristics dominate, and faint to distinct mottles are present within 50 cm of the soil surface.

BCvj:This BC horizon occurs on clay to heavy clay parent materials. In this horizon mixing due to shrinking and swelling of clays is evident but the disruption of other horizons is insufficient to severely alter them. Evidence of mixing includes: 1) irregular shaped, randomly oriented, intrusions of displaced materials within the solum and 2) vertical cracks, often containing sloughed-in surface materials.

BCx:A BC horizon of fragipan character.

BCxg:A BC horizon of fragipan character which shows dull, gray colors, or prominent mottling, or both within 50 cm of the soil surface, indicating permanent of periodic intense reduction.

BCy:A BC horizon affected by cryoturbation as manifested by a disrupted and broken horizon, incorporation of materials from other horizons, and mechanical sorting in at least half of the pedon. The B horizon characteristics are dominant.

Bf:A B horizon commonly found in podzolic soils that has: 1) a moist crushed color of black, a hue of 7.5YR or redder, or a hue of 10YR near the horizon boundary becoming yellower with depth. 2) amorphous material with brown to black coatings on grains or aggregates and a silty feel when rubbed wet. 3) ≥ 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and ≥ 0.4% in sands. Organic C ranges between 0.5 and 5%. 4) ≥ 10 cm in depth (depth satisfies the podzolic B criteria).

Bfc:An irreversibly cemented B horizon commonly found in podzolic soils. Horizons denoted as Ortstein are light to very dark reddish brown, strongly cemented and laterally occupy 1/3 of the pedon. Placic horizons include single thin layers (≤ 5mm), or series of thin layers that are irregular, hard, vitreous, dark reddish brown to black and cemented by Fe, Al-organic complexes. This horizon has the following dominant featuers: 1) a moist crushed color of black, a hue of 7.5YR or redder, or a hue of 10YR near the horizon boundary becoming yellower with depth. 2) amorphous material with brown to black coatings on grains or aggregates and a silty feel when rubbed wet. 3) ≥ 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and ≥ 0.4% in sands. Organic C ranges between 0.5 and 5%. 4) ≥ 10 cm in depth (depth satisfies podzolic B criteria).

Bfcc:A B horizon commonly found in podzolic soils that has: 1) a moist crushed color of black, a hue of 7.5YR or redder, or a hue of 10YR near the horizon boundary becoming yellower with depth. 2) amorphous material with brown to black coatings on grains or aggregates and a silty feel when rubbed wet. 3) ≥ 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and ≥ 0.4% in sands. Organic C ranges between 0.5 and 5%. 4) ≥ 10 cm in depth (depth satisfies podzolic B criteria). 5) pedogenic concretions of chemical compounds such as CaCO₃ or iron oxide in the form of nodules.

Bfcgj:A B horizon found in Gleyed Ortstein podzolic subgroups. It is irreversibly cemented and denoted as Ortstein, which means it's light to very dark reddish brown, strongly cemented and laterally occupies 1/3 of the pedon. Dominant features are: 1) a moist crushed color of black, a hue of 7.5YR or redder, or a hue of 10YR near the horizon boundary becoming yellower with depth. 2) amorphous material with brown to black coatings on grains or aggregates and a silty feel when rubbed wet. 3) ≥ 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and ≥ 0.4% in sands. Organic C ranges between 0.5 and 5%. 4) ≥ 10 cm in depth (depth satisfies podzolic B criteria). Secondary features of this horizon include faint to distinct mottles within 50 cm of the soil surface.

Bfg:A B horizon dominantly affected by frequent saturation and the accumulation of Fe and Al. It is commonly found in podzolic soils characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. Other key features include: 1) a moist crushed color of black, a hue of 7.5YR or redder, or a hue of 10YR near the horizon boundary becoming yellower with depth. 2) amorphous material with brown to black coatings on grains or aggregates and a silty feel when rubbed wet. 3) ≥ 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and ≥ 0.4% in sands. Organic C ranges between 0.5 and 5%. 4) ≥ 10 cm in depth (depth satisfies podzolic B criteria).

Bfgj:A B horizon commonly found in podzolic soils that has: 1) a moist crushed color of black, a hue of 7.5YR or redder, or a hue of 10YR near the horizon boundary becoming yellower with depth. 2) amorphous material with brown to black coatings on grains or aggregates and a silty feel when rubbed wet. 3) ≥ 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and ≥ 0.4% in sands. Organic C ranges between 0.5 and 5%. 4) ≥ 10 cm in depth (depth satisfies podzolic B criteria). Secondary features of this horizon include faint to distinct mottles within 50 cm of the soil surface.

Bfj:This B horizon commonly found in podzolic soils has some accumulation of pyrophosphate-extractable Al+Fe (< 0.6% for texture finer than sand and < 0.4% for sand), but not enough to meet the limits of a true Bf horizon.

Bfjcjgj:It is possible to find this B horizon in Gleyed Ortstein Humo-Ferric Podzols. It shows faint to distinct mottles within 50 cm of the soil surface, is weakly cemented or has weakly cemented thin layers within it, and is enriched with amorphous material (must be < 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and < 0.4% in sands), but not enough to satisfy a true Bf horizon.

Bgf:A B horizon found in Fera and Fera Humic Gleysols, as well as gleyed Podzols. It is prominently mottled, usually with more than half of the soil material occuring as mottles of high chroma. The pyrophosphate-extractable Al+Fe is < 0.6% in textures finer than sand and < 0.4% in sands (this is below the minimum requirement for a Bfg horizon). The Fe in this horizon is not associated intimately with organic matter or Al like it is in a Bfg.

Bgfc:An irreversibly cemented podzolic B horizon that is prominently mottled, usually with more than half of the soil material occuring as mottles of high chroma. It is denoted as Placic, which is a single thin layer (≤ 5mm), or a series of thin layers that are irregular, hard, vitreous, dark reddish brown to black and have hydrated Fe oxides. The pyrophosphate-extractable Al+Fe is < 0.6% in textures finer than sand and < 0.4% in sands.

Bgjss:This B horizon is mainly characterized by faint to distinct mottles within 50 cm of the soil surface. Two or more slickensides are also noticeable features. Slickensides are shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement, and they often intersect resulting in the formation of wedge shaped aggregates.

Bgjvj:This B horizon has no dominant features but is somewhat affected by saturation and mixing processes. Faint to distinct mottles are present within 50 cm of the soil surface, and mixing due to the shrinking and swelling of clays is evident but does not affect the development of other horizons. Evidence of mixing includes: 1) intrusions of displaced materials within the solum and 2) vertical cracks.

Bgss:This horizons dominant features are dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. Other important features are the presence of two or more slickensides, which are shear surfaces, with an aerial extent of at least 4 cm² that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and often intersect, resulting in the formation of wedge shaped aggregates.

Bgvj:A B horizon primarily affected by the presence of water, and characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. Secondary processes include mixing due to shrinking and swelling of clays. Disruption is evident in this horizon, but is not sever enough to alter other horizons. Evidence of mixing includes 1) intrusions of displaced materials within the solum and 2) vertical cracks.

Bh:A B horizon enriched with organic matter. It contains > 1% organic C and < 0.3% pyrophosphate-extractable Fe. Generally the color value and chroma are ≤ 3 when moist. This horizon is considered a podzolic B horizon if it is ≥ 10 cm in depth.

Bhc:An irreversibly cemented B horizon denoted as Ortstein which is generally light to very dark reddish brown, strongly cemented and laterally occupies 1/3 of the pedon. It is enriched with organic matter containing > 1% organic C and < 0.3% pyrophosphate-extractable Fe. It is considered a podzolic B horizon if it is ≥ 10 cm in depth.

Bhf:A B horizon commonly found in podzolic soils that has: 1) a moist crushed color of black, a hue of 7.5YR or redder, or a hue of 10YR near the horizon boundary becoming yellower with depth. 2) accumulation of amorphous material showing brown to black coatings on grains or microaggregates, and a silty feeling when rubbed wet. 3) ≥ 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and ≥ 0.4% in sands. Organic C is > 5%. 4) ≥ 10 cm in depth (depth satisfies podzolic B criteria).

Bhfc:An irreversibly cemented B horizon commonly found in podzolic soils. Horizons denoted as Ortstein are light to very dark reddish brown, strongly cemented and laterally occupy 1/3 of the pedon. Placic horizons are single thin layers (≤ 5mm), or series of thin layers that are irregular, hard, vitreous, dark reddish brown to black and cemented by Fe, Al-organic complexes. Dominant features of this horizon are: 1) a moist crushed color of black, a hue of 7.5YR or redder, or a hue of 10YR near the horizon boundary becoming yellower with depth. 2) accumulation of amorphous material showing brown to black coatings on grains or microaggregates, and a silty feeling when rubbed wet. 3) ≥ 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and ≥ 0.4% in sands. Organic C is > 5%. 4) ≥ 10 cm in depth (depth satisfies podzolic B criteria).

Bhfg:A B horizon primarily affected by the accumulation of Fe, Al and organic matter, as well as the presence of water. Dominant features include: 1) a moist crushed color of black, a hue of 7.5YR or redder, or a hue of 10YR near the horizon boundary becoming yellower with depth. 2) accumulation of amorphous material showing brown to black coatings on grains or microaggregates, and a silty feeling when rubbed wet. 3) ≥ 0.6% pyrophosphate-extractable Al+Fe in textures finer than sand and ≥ 0.4% in sands. Organic C is > 5%. 4) ≥ 10 cm in depth (depth satisfies podzolic B criteria). 5) prominent mottling within 50 cm of the soil surface indicating permanent or periodic intense reduction.

Bhjfj:A horizon that has features that are similar to by fail to meet the specific criteria for a Bh and Bf horizon (which are diagnostic of the Podzolic order). The j suffix can be though of as indicating juvenile versions of these horizons.

Bkgjss:The B horizon is primarily characterized by the presence of carbonates and effervescence when dilute HCl is added. Secondary features include faint to distinct mottles within 50 cm of the soil surface, as well as more than two slickensides. Slickensides are shear surfaces, with an aerial extent of at least 4 cm2 that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and intersect, resulting in the formation of wedge shaped aggregates.

Bm and Bmk:A horizon slightly altered by chemical weathering to give a change in color and/or structure. It has the following properties: 1) higher chromas and redder hues than the original parent materials, 2) removal of carbonates either partially (Bmk) or completely (Bm) and hence little or no reaction with dilute HCl, 3) a change in structure from that of the original material and 4) very little illuviation, if any.

Bmg and Bg:This horizon is analogous to a Bm horizon but has dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. These horizons are most often found in depressional areas subject to frequent saturation.

Bmgj or Bgj:A B horizon showing dominant features of: 1) higher chromas and redder hues than the original parent materials, 2) removal of carbonates, 3) a change in structure from the original material, and 4) very little illuviation, if any. Secondary features include faint to distinct mottling within 50 cm of the soil surface.

Bmkgj:This horizon is slightly altered by chemical weathering to give a change in color and/or structure which includes the following properties: 1) higher chromas and redder hues than the original parent materials, 2) partial removal of carbonates, 3) a change in structure from that of the original material and 4) very little illuviation, if any. Secondary features of the horizon include faint to distinct mottles within 50 cm of the soil surface.

Bms:A B horizon with salts, including gypsum, which may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants. Other dominant features are: 1) higher chromas and redder hues than the original parent materials, 2) removal of carbonates, 3) a change in structure from the original material and 4) very little illuviation, if any.

Bmy:A B horizon affected by cryoturbation as manifested by a disrupted and broken horizon, incorporation of materials from other horizons, and mechanical sorting in at least half of the pedon. Other dominant properties are: 1) higher chromas and redder hues than the original parent materials, 2) removal of carbonates, 3) a change in structure from the original material or 4) very little illuviation, if any.

Bmz and Bmkz:A frozen B horizon with one or more of the following properties: 1) higher chromas and redder hues than the original parent materials, 2) partial (Bmkz) or complete (Bmz) removal of carbonates, 3) a change in structure from the original material and 4) very little illuviation, if any.

Bn:A horizon in which the presence of sodium has influenced the development of the horizon. Solonetzic B horizon properties are: 1) the ratio of exchangeable Ca to exchangeable Na is 10 or less, 2) prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) hard to very hard consistence when dry.

Bng:A B horizon prominently mottled, usually with more than half of the soil material occurring as mottles of high chroma. It also meets the criteria to qualify as a solonetzic B horizon: 1) the ratio of exchangeable Ca to exchangeable Na is 10 or less, 2) prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) hard to very hard consistence when dry.

Bngjss:The presence of sodium is the dominant feature of this B horizon. Solonetzic B horizons include: 1) ratios of exchangeable Ca to exchangeable Na as 10 or less, 2) prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) hard to very hard consistence when dry. Secondary features include faint to distinct mottles within 50 cm of the soil surface, as well as the presence of more than two slickensides. Slickensides are shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. Slickensides often intersect resulting in the formation of wedge shaped aggregates.

Bnjtj:This horizon has no dominant characteristics, but is somewhat affected by the presence of sodium and illuviation. Characteristics include some illuviation of clay (i.e., more clay in the B horizon than the overlying Ae or Aej) but not enough to meet the limits of Bt, and an enrichment of sodium (the ratio of exchangeable Ca to exchangeable Na is > 10) possibly resulting in a hard prismatic structure.

Bnjtjgj:This horizon has no dominant characteristics, but is somewhat affected by the presence of sodium, illuviation and occasional saturation. Characteristics include faint to distinct mottles within 50 cm of the soil surface, some illuviation of clay (i.e., more clay in the B horizon than the overlying Ae or Aej) but not enough to meet the limits of Bt, and an enrichment of sodium (the ratio of exchangeable Ca to exchangeable Na is > 10) possibly resulting in a hard prismatic structure.

Bnsa:A horizon in which the presence of sodium has influenced the development of the horizon (n suffix) and which has secondary deposition of salts (sa suffix) evident. Solonetzic B horizon properties are: 1) the ratio of exchangeable Ca to exchangeable Na is 10 or less, 2) prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) hard to very hard consistence when dry.

Bnsak:A horizon in which the presence of sodium has influenced the development of the horizon (n suffix) and which has secondary deposition of salts (sa suffix) evident and primary carbonates (k suffix) present. Solonetzic B horizon properties are: 1) the ratio of exchangeable Ca to exchangeable Na is 10 or less, 2) prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) hard to very hard consistence when dry.

Bnss:A solonetzic B horizon with more than two slickensides present. Solonetzic B properties include: 1) a ratio of exchangeable Ca to exchangeable Na ≤ 10, 2) a prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) a hard to very hard consistence when dry. Slickensides are shear surfaces with an aerial extent of at least 4 cm2, that form when one soil mass moves over another.

Bnt:A B horizon primarily formed by illuviation and the presence of sodium. The dominant characteristics of this horizon include: 1) > 5 cm thick, 2) usually has a higher ratio of fine clay to total clay than the original parent material, 3) the ratio of exchangeable Ca to exchangeable Na is ≤ 10, 4) has prismatic or columnar structure, 5) dark coatings on ped surfaces, and 6) hard to very hard consistence when dry.

Bntg:A B horizon primarily formed by illuviation, the presence of sodium and "gley" processes. The dominant characteristics of this horizon include: 1) > 5 cm thick, 2) usually has a higher ratio of fine clay to total clay than the original parent material, 3) the ratio of exchangeable Ca to exchangeable Na is ≤ 10, 4) has prismatic or columnar structure, 5) dark coatings on ped surfaces, and 6) hard to very hard consistence when dry, 7) dull, grayish colors (chroma usually ≤ 2) and/or prominent mottles within 50 cm of the soil surface indicating permanent or periodic intense reduction.

Bntgj:A B horizon primarily formed by illuviation and the presence of sodium. The dominant characteristics of this horizon include: 1) > 5 cm thick, 2) usually has a higher ratio of fine clay to total clay than the original parent material, 3) the ratio of exchangeable Ca to exchangeable Na is ≤ 10, 4) has prismatic or columnar structure, 5) dark coatings on ped surfaces, and 6) hard to very hard consistence when dry. Secondary features of this horizon include faint to distinct mottles within 50 cm of the soil surface.

Bntgjss:A B horizon primarily formed by illuviation and the presence of sodium. The dominant characteristics of this horizon include: 1) > 5 cm thick, 2) usually has a higher ratio of fine clay to total clay than the original parent material, 3) the ratio of exchangeable Ca to exchangeable Na is ≤ 10, 4) has prismatic or columnar structure, 5) dark coatings on ped surfaces, and 6) hard to very hard consistence when dry. Secondary features of this horizon include faint to distinct mottles within 50 cm of the soil surface, as well as more than two slickensides which are described as shear surfaces with an aerial extent of at least 4 cm2, that form when one soil mass moves over another.

Bntgjvj:This B horizon is sometimes found in gleyed, Vertic Solonetz great groups. It is primarily affected by the presence of sodium and illuviation. Dominant features of this horizon are: 1) ratios of exchangeable Ca to exchangeable Na of 10 or less, 2) prismatic or columnar structures, 3) dark coatings on ped surfaces, 4) hard to very hard consistences when dry, 5) a 5 cm depth, and 6) enrichment with silicate clay (the fine clay to total clay ratio is greater than in the original parent material). Secondary features of this horizon include faint to distinct mottles within 50 cm of the soil surface as well as intrusions of displaced materials within the horizon and vertical cracks. Shrinking and swelling of clays cause disruption, but not enough to alter other horizons.

Bntgvj:A B horizon primarily formed by illuviation, the presence of sodium and "gley" processes. The dominant characteristics of this horizon include: 1) > 5 cm thick, 2) usually has a higher ratio of fine clay to total clay than the original parent material, 3) the ratio of exchangeable Ca to exchangeable Na is ≤ 10, 4) has prismatic or columnar structure, 5) dark coatings on ped surfaces, and 6) hard to very hard consistence when dry, 7) dull, grayish colors (chroma usually ≤ 2) and/or prominent mottles within 50 cm of the soil surface indicating permanent or periodic intense reduction. Secondary disruption and mixing features are present due to the shrinking and swelling of clay in the soil. Evidence includes intrusions of displaced materials and vertical cracks within the horizon.

Bntj:A horizon that meets the criteria for a solonetzic B horizon (primarily a ratio of exchangeable calcium to exchangeable sodium of 10 or less) . It also shows evidence of clay deposition but the difference in clay between the Ae and B horizon is insufficient to meet the criteria for a true t suffix.

Bntss:An illuvial, solonetzic B horizon with more than two slickensides present. Dominant features include: 1) > 5 cm thick, 2) usually has a higher ratio of fine clay to total clay than the original parent material, 3) the ratio of exchangeable Ca to exchangeable Na is ≤ 10, 4) has prismatic or columnar structure, 5) dark coatings on ped surfaces, and 6) hard to very hard consistence when dry. Also, slickensides are described as shear surfaces with an aerial extent of at least 4 cm2, that form when one soil mass moves over another.

Bnvj:A solonetzic B horizon with the following properties: 1) a ratio of exchangeable Ca to exchangeable Na ≤ 10, 2) a prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) a hard to very hard consistence when dry. Secondary features include mixing and disruption caused by the shrinking and swelling of clay. Evidence includes intrusions of displaced materials and vertical cracks within the horizon.

Bss:A B horizon characterized by the presence of more than two slickensides. Slickensides are shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and often occur at an angle of 20 to 60 degrees from the horizontal. They often intersect, resulting in the formation of wedge shaped aggregates.

Bssg:This horizon is characterized by the presence of more than two slickensides, and typical "gley" features resulting from frequent soil saturation. Slickensides are shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and intersect, resulting in the formation of wedge shaped aggregates. Permanent or periodic intense reduction results in soil with dull, grayish colors (chroma usually ≥ 2) and/or prominent mottling within 50 cm of the soil surface.

Bssgj:This B horizon is primarily identified by the presence of more than two slickensides, which are shear surfaces with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and intersect, resulting in the formation of wedge shaped aggregates. Secondary features include faint to distinct mottles within 50 cm of the soil surface due to occasional soil saturation and reduction processes.

Bssk:This horizon is distinguished primarily by the presence of more than two slickensides and its calcium carbonate content. Slickensides are shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement, and intersect, resulting in the formation of wedge shaped aggregates. Calcium carbonate is indicated by effervescence when dilute HCl is added to the exposed soil.

Bsskgj:This horizon is primarily characterized by the presence of more than two slickensides and its reaction with dilute HCl due to the presence of calcium carbonate throughout. Slickensides are shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and intersect, resulting in the formation of wedge shaped aggregates. Secondary features include the presence of faint to distinct mottles within 50 cm of the soil surface due to occasional saturation.

Bt:

A Bt horizon is one that contains illuvial layer lattice clays. It forms below an eluvial horizon but may occur at the surface of a soil that has been partially truncated. It usually has a higher ratio of fine clay to total clay than the IC. It has the following properties:

1. If any part of an eluvial horizon remains and there is no lithologic discontinuity between it and the Bt horizon, the Bt horizon contains more total clay than the eluvial horizon as follows:

a. If any part of the eluvial horizon has less than 15% total clay in the fine earth fraction (<2 mm), the Bt horizon must contain at least 3% more clay (e.g., Ae 10% clay; Bt minimum 13% clay). b.If the eluvial horizon has more than 15% and less than 40% total clay in the fine earth fraction, the ratio of the clay in the Bt horizon to that in the eluvial horizon must be 1.2 or more (e.g., Ae 25% clay; Bt at least 30% clay). c. If the eluvial horizon has more than 40% total clay in the fine earth fraction, the Bt horizon must contain at least 8% more clay (e.g., Ae 50% clay; Bt at least 58% clay).

2. A Bt horizon must be at least 5 cm thick. In some sandy soils where clay accumulation occurs in the lamellae, the total thickness of the lamellae should be more than 10 cm in the upper 1.5 m of the profile.

3. In massive soils the Bt horizon should have oriented clay in some pores and also as bridges between the sand grains.

4. If peas are present, a Bt horizon has clay skins on some of the vertical and horizontal ped surfaces and in the fine pores or has illuvial oriented clays in 1% or more of the cross section as viewed in thin section.

5. If a soil shows a lithologic discontinuity between the eluvial horizon and the Bt horizon, or if only a plow layer overlies the Bt horizon, the Bt horizon need show only clay skins in some part, either in some fine pores or on some vertical and horizontal ped surfaces. Thin sections should show that the horizon has about 1% or more of oriented clay bodies.

Btg:A gleyed, illuvial B horizon characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. It must be enriched with silicate clay and be > 5 cm thick, usually having a higher ratio of fine clay to total clay than the original parent material. If soil structural units (peds) are present, it would have clay skins on some of the vertical and horizontal ped surfaces.

Btgjvj:An illuvial B horizon > 5 cm in depth, characterized by enrichment with silicate clay, usually having a higher ratio of fine clay to total clay than the original parent material. Secondary features include faint to distinct mottles within 50 cm of the soil surface as well as weak disruption features due to the shrinking and swelling of clay.

Btgss:A gleyed, illuvial B horizon characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. It must be enriched with silicate clay and be > 5 cm thick, usually having a higher ratio of fine clay to total clay than the original parent material. More than two slickensides are present, which are shear surfaces with an aerial extent of at least 4 cm2, that form when one soil mass moves over another.

Btgvj:A B horizon primarily affected by illuviation and "gley" processes. Illuvial features of this horizon include a depth > 5 cm and enrichment with silicate clay, usually containing a higher ratio of fine clay to total clay than the original parent material. Gley processes result in dull and grayish colors (chroma usually ≤ 2) and/or prominent mottles within 50 cm of the soil surface indicating permanent or periodic intense reduction. Secondary features result from mixing due to the shrinking and swelling of clay parent materials. Evidence includes intrusions of displaced materials and vertical cracks within the horizon.

Btgx:A gleyed, illuvial, fragipan B horizon characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. It must be enriched with silicate clay and be > 5 cm thick, usually having a higher ratio of fine clay to total clay than the original parent material.

Btj:It is a horizon with some illuviation of clay (i.e., more clay in the B horizon than the overlying Ae or Aej) but not enough to meet the limits of Bt. There are quantitative laboratory criteria for this horizon in the CSSC manual.

Btjgj:A B horizon with no distinct features. It does have some illuviation of clay (i.e., more clay in the B horizon than the overlying Ae or Aej) but not enough to meet the limits of Bt. As well as faint to distinct mottles within 50 cm of the soil surface.

Btjnj:A B horizon with no dominant characteristics but is subject to illuviation and sodium enrichment. There is some illuviation of clay (i.e., more clay in the B horizon than the overlying Ae or Aej) but not enough to meet the limits of Bt. The development of solonetzic B properties is evident but insufficient to meet the limits for Bnt. Solonetzic B properties are: 1) the ratio of exchangeable Ca to exchangeable Na is 10 or less, 2) prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) hard to very hard consistence when dry.

Btnj or Bnj:In these horizons the development of Solonetzic B properties is evident but are insufficient to meet the limits for Bn or Bnt. Solonetzic B horizon properties are: 1) the ratio of exchangeable Ca to exchangeable Na is 10 or less (based on a laboratory analysis), 2) prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) hard to very hard consistence when dry.

Btnjgj:A B horizon dominated by illuvial processes. Dominant features include a depth > 5 cm and enrichment with silicate clay, usually containing a higher ratio of fine clay to total clay than the original parent material. Secondary features include the development of solonetzic B properties: 1) the ratio of exchangeable Ca to exchangeable Na is 10 or less, 2) prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) hard to very hard consistence when dry. As well, there are faint to distinct mottles present within 50 cm of the soil surface.

Btss:A B horizon characterized by illuviation of material and the presence of more than two slickensides. The dominant characteristics include: 1) > 5 cm depth, 2) enrichment with silicate clay, containing a higher ratio of fine clay to total clay than the original parent material, 3) 2 or more slickensides, which are shear surfaces with an aerial extent of at least 4 cm2, that form when one soil mass moves over another, 4) the presence of wedge shaped aggregates due to slickenside intersection.

Btxgj:A B horizon primarily affected by illuviation and showing a fragipan character. Illuvial characteristics include a depth > 5 cm and enrichment with silicate clay, usually containing a higher ratio of fine clay to total clay than the original parent material. Secondary features include faint to distinct mottles within 50 cm of the soil surface.

Bv:This horizon occurs on clay to heavy clay parent materials. Mixing due to shrinking and swelling of clays is evident and the disruption of other horizons can be sufficient to severely alter them or prevent their development. Evidence of mixing includes: 1) irregular shaped, randomly oriented, intrusions of displaced materials within the solum and 2) vertical cracks, often containing sloughed-in surface materials.

Bvg:A B horizon characterized by gray colors, or prominent mottling, or both within 50 cm of the soil surface, indicating permanent of periodic intense reduction. This horizon also occurs on clay to heavy clay parent materials. In this horizon mixing due to shrinking and swelling of clays is evident and the disruption of other horizons can be sufficient to severely alter them or prevent their development. Evidence of mixing includes: 1) irregular shaped, randomly oriented, intrusions of displaced materials within the solum and 2) vertical cracks, often containing sloughed-in surface materials.

Bvgj:A B horizon primarily affected by mixing due to shrinking and swelling of clays. Disruption of other horizons can be sufficient to severely alter them or prevent their development. Evidence of mixing includes: 1) irregular shaped, randomly oriented, intrusions of displaced materials within the solum and 2) vertical cracks, often containing sloughed-in surface materials. Secondary features include faint to distinct mottles occurring within 50 cm of the soil surface.

Bvj:This horizon occurs on clay to heavy clay parent materials. In this horizon mixing due to shrinking and swelling of clays is evident but the disruption of other horizons is insufficient to severely alter them. Evidence of mixing includes: 1) irregular shaped, randomly oriented, intrusions of displaced materials within the solum and 2) vertical cracks, often containing sloughed-in surface materials.

Bvk:This B horizon occurs on clay to heavy clay, carbonate rich parent materials. In this horizon mixing due to shrinking and swelling of clays is evident and the disruption of other horizons can be sufficient to severely alter them or prevent their development. Evidence of mixing includes: 1) irregular shaped, randomly oriented, intrusions of displaced materials within the solum and 2) vertical cracks, often containing sloughed-in surface materials. This horizon also contains primary calcium carbonate where the amount of effervescence when dilute HCl is added is consistent throughout the depth of the horizon.

Bvkgj:A B horizon primarily affected by clayey and carbonate rich parent materials. Mixing due to shrinking and swelling of clays results in the disruption of other horizons, irregular shaped, randomly oriented, intrusions of displace materials within the solum and vertical cracks, often containing sloughed-in surface materials. Primary carbonates are observed by effervescence when dilute HCl is added to the soil. Secondary features include faint to distinct mottles within 50 cm of the soil surface.

Bx:A B horizon with a fragipan. A fragipan is A loamy subsurface horizon of high bulk density and very low organic matter content. When dry, it is of hard consistence and seems to be cemented, and when moist, it has moderate to weak brittleness. It frequently has fractures with bleached surfaces and is overlain by a B horizon that crumbles easily under pressure.

Bxg:A B horizon of fragipan character which shows dull, gray colors, or prominent mottling, or both within 50 cm of the soil surface, indicating permanent of periodic intense reduction.

By:A B horizon affected by cryoturbation as manifested by a disrupted and broken horizon, incorporation of materials from other horizons, and mechanical sorting in at least half of the pedon.

C:A C horizon is a mineral horizon meaning it contains ≤ 17% organic C (about 30% organic matter) by weight. It is comparatively unaffected by the pedogenic processes operating in A and B horizons, except the process of gleying (Cg) and accumulation of calcium and magnesium carbonates (Cca) and more soluble salts (Cs, Csa). Marl, diatomaceous earth, and rock with a hardness ≤ 3 on Mohs' scale are considered to be C horizons.

Carbon and Organic Matter:Living organisms contribute organic materials to the soil � roots, leaves, microorganisms, and larger animals. The freshly added organic matter typically undergoes a series of transformation through microbial processes. These processes liberate essential nutrients from the organic matter and leave behind less palatable organic materials and organic by-products. Carbon is typically used as a measure of total organic matter, and often organic carbon and organic matter are used interchangeably in soil science.

Carbonates and salts:Carbonates and salts are particular types of minerals found in soils. They are composed of an anion (Cl-, SO4-, CO3-) bound to a cation (Ca2+, Mg2+, Na+, K+) and the share a property that they readily dissolve in water into their constituent ions. Carbonates (CaCO3, MgCO3) are a salt that slowly moves into solution, whereas salts like NaCl move readily into solution. The dissolved ions can be moved with the water, and where the water is lost through evaporation or plant transpiration the mineral salts can reform through precipitation processes. This can lead to carbonation and salinization of soils.

Catena:Soils of different taxonomic classes often occur in close and repetitive association with each other. These soils occur like links in a chain, and the Latin word for chain, catena, was adopted to describe this association. The most common catenas result from differences in water and sediment redistribution associated with topographical position and form in the landscape.

Cca:A horizon of secondary calcium carbonate (CaCO₃, also known as lime) enrichment in which the concentration of lime exceeds that in the unenriched parent material (typically a Ck horizon) and which is more than 10 cm thick. The horizon shows visible effervescence in the field when dilute HCl is added. The full CSSC manual contains quantitative laboratory criteria for this horizon.

Ccag:A horizon characterized by gray colors, or prominent mottling, or both within 50 cm of the soil surface, indicating permanent of periodic intense reduction. It also has secondary calcium carbonate (CaCO₃, also known as lime) enrichment in which the concentration of lime exceeds that in the unenriched parent material (typically a Ck horizon) and which is more than 10 cm thick. It shows visible effervescence in the field when dilute HCl is added.

Cg:A C horizon characterized by dull, grayish colors and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. Chromas of the matrix are generally ≤ 2. In some reddish parent materials, matrix colors of reddish hues and high chromas may persist despite long periods of reduction. In these horizons gray mottling or marked bleaching on ped faces or along cracks are sufficient.

Cgj:A C horizon with faint to distinct mottles within 50 cm of the soil surface.

Cgsk:A C horizon characterized by gley features, the presence of salts, and carbonates. The dominant features include dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50cm of the soil surface, indicating permanent or periodic intense reduction. The presence of salts including gypsum, which may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants. The presence of primary calcium carbonate originating from the soil parent material, which is detected by effervescence when dilute HCl is added to the soil.

Cgss:A C horizon characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50cm of the soil surface, indicating permanent or periodic intense reduction. It also has more than two slickenside features which are shear surfaces with an areal extent of at least 4 cm2, that form when one soil mass moves over another.

Cgy:A C horizon characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50cm of the soil surface, indicating permanent or periodic intense reduction. It is affected by cryoturbation as manifested by a disrupted and broken horizon, incorporation of materials from other horizons, and mechanical sorting in at least half of the pedon.

Chernozemic A horizon:An A horizon of the Chernozemic order which meets the following criteria: 1) at least 10 cm thick. 2) color value (Munsell notation) that is less than 5.5 when dry, and 3.5 moist. 3) contains > 1% and < 17% organic C. 4) has good structure (usually granular). 5) has a base saturation > 80%, and calcium is the main exchangeable cation.

Ck:A horizon with primary calcium carbonate inherited from the soil parent materials. The amount of effervescence when dilute HCl is added is constant throughout the depth of the horizon.

Ckg:A horizon with primary calcium carbonate inherited from the soil parent materials. The amount of effervescence when dilute HCl is added is constant throughout the horizon depth. It is characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50cm of the soil surface, indicating permanent or periodic intense reduction.

Ckgj:A horizon primarily identified by the presence of primary calcium carbonate inherited from the soil parent materials. The amount of effervescence when dilute HCl is added is constant throughout the horizon depth. Secondary features include faint to distinct mottles within 50 cm of the soil surface.

Ckgjss:A C horizon primarily identified by the presence of primary calcium carbonates. Carbonates originating from the original soil parent material are evident upon reaction with dilute HCl. Secondary features include faint to distinct mottles within 50 cm of the soil surface as well as more than two slickensides. Slickensides are described as shear surfaces with an areal extent of at least 4 cm2, that form when one soil mass moves over another.

Ckss:A C horizon characterized by the presence of primary carbonates and more than two slickensides. Calcium carbonate originated from the soil parent material is evident upon reaction with a dilute HCl. Slickensides are described as shear surfaces with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and intersect, resulting in the formation of wedge shaped aggregates.

Ckssgj:A C horizon characterized by the presence of primary carbonates and more than two slicensides. Calcium carbonate originated from the soil parent material is evident upon reaction with a dilute HCl solution. Slickensides are described as shear surfaces with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and intersect, resulting in the formation of wedge shaped aggregates. Secondary features include faint to distinct mottles within 50 cm of the soil surface.

Columnar structure:Characterized by smooth vertical edges near the top of column structure with flat, round or irregular tops.

Cs:A C horizon with salts, including gypsum, which may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants.

Csa:A horizon with secondary enrichment of salts more soluble than Ca and Mg carbonates; the concentration of salts exceeds that in the unenriched parent material. The horizon must be at least 10 cm thick. There are quantitative laboratory criteria for this in the full CSSC manual.

Csag:A C horizon ≥ 10 cm, characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50cm of the soil surface, indicating permanent or periodic intense reduction. Secondary enrichment of salts more soluble than Ca and Mg carbonates are present and the concentration of salts exceeds that in the unenriched parent material.

Csagj:A ≥ 10 cm C horizon primarily characterized by a secondary enrichment of salts more soluble than Ca and Mg carbonates; the concentration of salts exceeds that in the unenriched parent material. Secondary features include faint to distinct mottles within 50 cm of the soil surface.

Csak:A horizon with secondary enrichment of salts more soluble than Ca and Mg carbonates; the concentration of salts exceeds that in the unenriched parent material. The horizon must be at least 10 cm thick. This horizon also contains primary calcium carbonate inherited from the soil parent material. The amount of effervescence when dilute HCl is added is constant throughout the horizon depth.

Csg:A C horizon characterized by dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50cm of the soil surface, indicating permanent or periodic intense reduction. Salts, including gypsum are present, and may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants. Saturation plays an important role in the physical state of the salts.

Csgj:A C horizon primarily characterized by the presence of salts, including gypsum, which may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants. Secondary features include faint to distinct mottles within the upper 50 cm of the soil profile.

Csk:A horizon with salts, including gypsum, which may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants. Primary calcium carbonate inherited from the soil parent material is also present, resulting in constant effervescence throughout the horizon when dilute HCl is added.

Cskg:A C horizon identified by the presence of salts, carbonates and mottles. Salts, including gypsum, may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants. Primary calcium carbonate inherited from the soil parent material produced constant effervescence with depth as dilute HCl is added. It also has dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50cm of the soil surface, indicating permanent or periodic intense reduction.

Cskgj:A C horizon primarily identified by the presence of salts and carbonates. Salts, including gypsum, may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants. Primary calcium carbonate inherited from the soil parent material produced constant effervescence with depth as dilute HCl is added. Secondary features of this horizon include faint to distinct mottles within 50 cm of the soil surface.

Cskgjss:The dominant features of this horizon are the presence of salt and carbonates. Salts, including gypsum, may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants. Carbonates originating from the soil parent material are detected by effervescence with dilute HCl addition. Secondary features are the presence of faint to distinct mottles within 50 cm of the soil surface, as well as more than two slickensides which are described as shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another.

Cskss:A C horizon characterized by the presence of salts, primary carbonates and more than two slickensides. Salts, including gypsum, may be detected as crystals or veins, as surface crusts of salt crystals, by depressed crop growth, or by the presence of salt-tolerant plants. Carbonates originating from the soil parent material are detected by effervescence with dilute HCl addition. Slickensides are described as shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another.

Css:A C horizon with the presence of more than two slickensides. Slickensides are shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and often occur at an angle of 20 to 60 degrees from the horizontal. Slickensides often intersect, resulting in the formation of wedge shaped aggregates that commonly occur in these soils. It is used with C alone (Css), with C and other lower case suffixes (Cssk, Cssgj, Csskgj, Ctss, etc).

Cssg:This horizons dominant features are dull, grayish colors (chroma usually ≤ 2) and/or prominent mottling within 50 cm of the soil surface, indicating permanent or periodic intense reduction. Other important features are the presence of two or more slickensides, which are shear surfaces, with an aerial extent of at least 4 cm2 that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement and often intersect, resulting in the formation of wedge shaped aggregates.

Cssgj:This C horizon is characterized by faint to distinct mottles within 50 cm of the soil surface and the presence of two or more slickensides. Slickensides are shear surfaces, with an aerial extent of at least 4 cm2, that form when one soil mass moves over another. They commonly display unidirectional grooves parallel to the direction of movement, and they often intersect resulting in the formation of wedge shaped aggregates.

Cumulic layer:This is a layer or layers of mineral material in organic soils. Either the combined thickness of the mineral layers is more than 5 cm or a single mineral layer 5-30 cm thick occurs. One continuous mineral layer more than 30 cm thick in the middle or bottom tier is a terric layer.

Cv:A C horizon that occurs on clay to heavy clay parent materials. In this horizon mixing due to shrinking and swelling of clays is evident and the disruption of other horizons can be sufficient to severely alter them or prevent their development. Evidence of mixing includes: 1) irregular shaped, randomly oriented, intrusions of displaced materials within the solum and 2) vertical cracks, often containing sloughed-in surface materials.

Cy:A C horizon affected by cryoturbation as manifested by a disrupted and broken horizon, incorporation of materials from other horizons, and mechanical sorting in at least half of the pedon.

Cz:A frozen C horizon.

Duric horizon:A strongly cemented horizon that usually has an abrupt upper boundary to an overlying podzolic B or to a Bm horizon, and a diffuse lower boundary more than 50 cm below. Cementation is usually strongest near the upper boundary which is typically within 40-80 cm of the soil surface. The color usually doesn't vary from the parent material, and the structure is usually massive or very coarse platy. Moist clods 3 cm thick normally can't be broken in the hands.

Effervescence:The visible result of adding HCl to carbonate-containing soil. The acid reacts on the surface and produces bubbles. The bubbles generate quicker and larger in size when there is an increase in soil carbonates.

Eluvial and eluviation:Eluviation is the transfer of material out from a horizon. For example, the Ae is an eluvial horizon which may have lost clay, iron, or aluminum.

Extremely calcareous:A CaCO3 equivalent % > 40.

F:This organic horizon is characterized by an accumulation of partly decomposed organic matter. Some of the original structures are difficult to recognize. The material may be partly comminuted (pulverized) by soil fauna as in moder (a non-matted forest humus), or it may be a partly decomposed mat permeated by fungal hyphae as in mor.

Fluvial and glacio-fluvial:Sediments deposited in flowing water environments (rivers); deposits associated with glacial episodes called glacio-fluvial. Fluvial sediments are typically well- sorted gravels and sands,. Well-sorted means that one particle size (e.g. sand) is dominant in the texture.

Fragipan:A loamy subsurface horizon of high bulk density and very low organic matter content. When dry, it is of hard consistence and seems to be cemented, and when moist, it has moderate to weak brittleness. It frequently has fractures with bleached surfaces and is overlain by a B horizon that crumbles easily under pressure.

Gley:Water saturation leads to depletion of oxygen in the soil and soil features associated with oxygen-depleted (also called anaerobic or anoxic) conditions. Anaerobic conditions cause the transformation of metals such as iron and (to a lesser degree) manganese and lead to changes in the dominant colour of soil horizons. When oxygen is present, iron is oxidized and has a reddish colour; when oxygen becomes depleted (due to water saturation) the iron is reduced and takes on a blue-grey hue and this dominates the colour of the horizon. Reduced iron is also mobile, and it can concentrate in the profile and re-oxidize, producing reddish or brown mottles. These features are collectively referred to as gley features.

H:This organic horizon is characterized by an accumulation of decomposed organic matter in which the original structures are indiscernible. This horizon differs from the F by having greater humification due chiefly to the action of organisms. It is frequently intermixed with mineral grains, especially near the junction with mineral horizons.

Humus:Humus is organic matter that has been transformed into an unrecognizable state through microbial decomposition processes. It is resistant to further change and can persist in the soil for many hundreds or thousands of years.

Hydric layer:This is a layer of water that extends from a depth of 40 cm from the organic surface to a depth of more than 1.6 m.

Illuvial and illuviation:Illuviation is the transfer of material into a horizon. The Bt horizon is an illuvial horizon which results from the deposition of clay transferred from the Ae horizon.

L:This organic horizon is characterized by an accumulation of organic matter in which the original structures are easily discernible.

L,F,H:An organic horizon containing > 17% organic C (approximately ≥ 30% organic matter) by weight. It is developed primarily from the accumulation of leaves, twigs, and woody materials with or without a minor component of mosses. It is also normally associated with upland forested soils with imperfect drainage or drier.

Lacustrine or Glacio-lacustrine:Parent materials deposited in lakes. Most lacustine parent materials in Canada were deposited in lakes that existed during the glacial periods and are called glacio-lacustrine sediments. Lacustrine sediments are typically well- sorted sands, silts, and clays. Well-sorted means that one particle size (e.g. clay) is dominant in the texture.

Limnic layer:This is a layer or layers, 5 cm or more thick, of coprogenous earth (sedimentary peat), diatomaceous earth, or marl. Most of these materials are inorganic. Coprogenous earth is composed of aquatic plant debris modified by aquatic animals. Diatomaceous earth is composed mainly of the silica shells of diatoms (planktonic single-celled algae). Marl is composed of the shells of aquatic animals and CaCO3 precipitated in water.

Lithological discontinuity:Lithological discontinuity is due to a different mode of deposition, indicated by strongly contrasting textures (differing by two textural classes), or to a different mineralogical composition, indicating a difference in the material from which the horizons have formed. These contrasting materials have resulted form geologic deposition rather than pedogenic processes.

A change in the clay content associated with a Bt horizon (textural B) does not indicate a difference in parent material. The appearance of gravel, or a change in the ratio between the various sand separates, normally suggests a difference in parent materials.

Roman numerals are prefixed to the contrasting master horizon or layer designation (A, B. C) to indicate lithological discontinuities either within or below the solum. The first, or uppermost, material is not numbered, because the Roman numeral I is understood; the second contrasting material is designated II, and the others are numbered consecutively, with depth. Thus, for example, a sequence from the surface downward might be Ah, Bm, IIBm, IICa, IICk, IIICk.

Loams and Loamy Parent Materials:The loam textural classes have mixtures of sand, silt, and clay in different proportions. The great majority of till parent materials in Canada are loams (loam, sandy loam, clay loam) because mixing and direct deposition by the ice does not sort the different particle sizes into distinct size classes (as would be the case in lacustrine or fluvial deposits).

Mottles:Features that occur in grey colored, gley soils when they are exposed to air resulting in the oxidation of Fe leaving reddish, yellow or orange patches in the soil profile.

Mull:This form of forest humus consists of a mixture of well-humified organic matter and mineral soil with crumb or granular structure that makes a gradual transition to the original parent material. Organic matter is usually 5-25% and the C:N ratio is 12-18 (It is a kind of Ah horizon). This layer is markedly mixed by the activities of earthworms and other burrowing microfauna.

Munsell Colour Contrast:This is the difference between the feature colour and the matrix colour and is assessed using Munsell colour charts.

Difference from matrix in

Hue Pages

Value Units

Chroma Units

Faint

0

≤ -2

≤ -1

1

0

0

Distinct

0

3-4

2-4

1

≤ 2

≤ 1

Prominent

0

≥ 4

≥ 4

1

≥ 4

≥ 4

2+

≥ 0

≥ 0

Munsell Colours:The Munsell system used to describe colour in soils. It is based on a continuous wheel of colour, which is subdivided into distinctive classes. The criteria used to group colour into classes are:

Hue: The dominant spectral (or rainbow) colour, which is related to the dominant wavelength of light. The colour wheel is split into distinct ranges of hue (e.g., YR for Yellow-Red or R for Red), each of which has 10 gradations (e.g., 1 YR, 5 YR, 10 YR). In the Munsell colour books used for soil description, each page of colour chips is one of these gradations of the hue range.

Value: The value refers to the relative lightness of the colour and varies from 0 (pure black) to 10 (pure white). The values are arranged along the vertical axis of the pages of the colour book.

Chroma: The chroma refers to the brightness (or strength) of the spectral colour; higher chromas for a given value indicate brighter colours. The chromas are arranged along the horizontal axis of the colour book.

Each colour chip in the Munsell book refers to a distinctive combination of hue, value and chroma and is reported as (for example) 10YR 3/2 -the hue is 10 YR, the value is 3 and the chroma is 2.

O:An organic horizon containing > 17% organic C (approximately ≥ 30% organic matter) by weight. It is developed mainly from mosses, rushes and woody materials, and is divided into 3 subhorizons (Of, Om and Oh) based on the material present and the stage of decomposition.

Oco:This organic horizon is coprogenous earth, which is a limnic material that occurs in some organic soils. It is deposited in water by aquatic organisms such as algae or derived from underwater and floating aquatic plants subsequently modified by aquatic animals.

Of:An organic horizon consisting largely of fibric materials that are readily identifiable as botanical materials. Fibric material is not well decomposed having a von Post scale of decomposition ranging from class 1 to 4. It has a rubbed fiber volume of > 40%. There are three kinds of fibric horizons: 1) Fennic horizons are derived from rushes, reeds, and sedges. 2) Silvic horizons are derived from wood, moss with < 75% volume being sphagnum. 3) Sphagnic horizons are derived from sphagnum mosses.

Ofk:An organic horizon containing fibric materials that are readily identifiable as botanical materials, and are not well decomposed (von Post scale of decomposition ranging from class 1 to 4). It also contains primary carbonates which show noticeable effervescence when dilute HCl is added to the horizon profile.

Ofp:An organic horizon that is disturbed by human activities such as cultivation, logging, and habitation. It contains fibric materials that are readily identifiable as botanical materials, and are not well decomposed (von Post scale of decomposition ranging from class 1 to 4).

Ofz:A frozen organic horizon containing fibric materials that are readily identifiable as botanical materials, and are not well decomposed (von Post scale of decomposition ranging from class 1 to 4).

Oh:An organic horizon consisting of humic material, which is at an advanced stage of decomposition. This horizon has the lowest amount of fiber, the highest bulk density, and the lowest saturated water-holding capacity of all three organic horizons. It is very stable and changes little physically or chemically with time unless it is drained. The rubbed fiber content is < 10% by volume. Humic material is usually classified on the von Post scale of decomposition as ≥ class 7, and rarely class 6.

Ohp:An organic horizon that is disturbed by human activities such as cultivation, logging, and habitation. It contains humic material, which is at an advanced stage of decomposition (von Post scale of decomposition ≥ class 7). It is high in bulk density, and has a low saturated water-holding capacity. It is very stable and changes little physically or chemically with time unless it is drained naturally or by human activity.

Ohz:A frozen organic horizon consisting of humic material, which is at an advanced stage of decomposition (von Post scale of decomposition ≥ class 7). It is high in bulk density, and has a low saturated water-holding capacity. It is very stable and changes little physically or chemically with time unless it is drained naturally or by human activity.

Om:An organic horizon consisting of mesic material, which is at a stage of decomposition intermediate between fibric and humic materials. It has a von Post scale of decomposition ranging from class 5 to 6. The material is partly altered both physically and biochemically. It's rubbed fiber volume ranges from 10% to 40%.

Omk:An organic horizon consisting of mesic material that is partly altered both physically and biochemically. It is at a stage of decomposition intermediate between fibric and humic materials (von Post scale of decomposition ranging from class 5 to 6). It also contains primary carbonates which show noticeable effervescence when dilute HCl is added to the horizon.

Omp:An organic horizon that is disturbed by human activities such as cultivation, logging, and habitation. It contains mesic material that is partly altered both physically and biochemically. It is at a stage of decomposition intermediate between fibric and humic materials (von Post scale of decomposition ranging from class 5 to 6).

Omy:An mesic organic horizon affected by cryoturbation as manifested by a disrupted and broken horizon, incorporation of materials from other horizons, and mechanical sorting in at least half of the pedon. The mesic material is defined as partly altered both physically and biochemically, and at a stage of decomposition intermediate between fibric and humic materials (von Post scale of decomposition ranging from class 5 to 6).

Omz:A frozen organic horizon consisting of mesic material that is partly altered both physically and biochemically. It is at a stage of decomposition intermediate between fibric and humic materials (von Post scale of decomposition ranging from class 5 to 6).

Ortstein horizon:This strongly cemented Bhc, Bhfc or Bfc horizon is at least 3 cm thick and occurs in more than one-third of the exposed face of the pedon. Ortstein horizons are generally reddish brown to very dark reddish brown.

pH:The pH is a measure of the hydrogen ion (H+) content of the soil. Soils with high H+ concentrations are considered acidic and soils with low H+ are considered alkaline or basic. The mid-point of the pH scale is a pH of 7, where the soil is considered to be neutral. Values of pH less than 7 indicate a H+ rich soil (or acidic conditions) and values greater than 7 indicate a alkaline or basic condition. Soil pH is originally determined by the parent material of the soil. Generally parent materials (glacial, fluvial etc.) derived from igneous rocks are often acidic where as parent materials derived from sedimentary rocks are alkaline or basic. The evolution of soil pH after the onset of soil formation is often determined by the soil forming processes.

Placic horizon:This horizon is a thin layer (commonly 5 cmm or less in thickness) or a series of thin layers that are irregular, hard, impervious, often vitreous, and dark reddish brown to black. Placic horizons may be cemented by Fe, Al-organic complexes (Bhfc or Bfc), hydrated Fe oxides (Bgfc), or a mixture of Fe and Mn oxides.

Platy structure:Is characterized by horizontal planes that are more or less developed.

Podzolic B horizon:This horizon is defined by morphological and chemical properties. Morphologically it has: 1) a 10 cm thickness. 2) a moist crushed color of black, or a hue of 7.5YR or redder or 10YR near the upper boundary becoming yellower with depth. 3) accumulation of amorphous material indicated by brown to black coatings on grains or microaggregates. There is a silty feel when wet, unless it is cemented. Chemically it can have either: 1) very low Fe (< 0.3% pyrophosphate-extractable Fe), and > 1% organic C. 2) very appreciable levels of Fe as well as Al (≥ 0.3% pyrophosphate-extractable Fe, ≥ 0.6% pyrophosphate-extractable Fe+Al in textures finer than sand, ≥ 0.4% in sand), and > 0.5% organic C.

R:An R horizon is a consolidated bedrock layer (lithic layer) that is too hard to break with the hands (> 3 on Mohs' scale) or to dig with a spade when moist. It does not meet the requirements of a C horizon, and it occurs within 10-160 cm of the surface. The boundary between the R layer and any overlying unconsolidated material is called a lithic contact.

Single grain structure:A loose, incoherent mass of individual particles as in sands.

Slickenslides:Morphological features found in clay or heavy clay soils and that form by shrinking and swelling processes in these soils. They are shear surfaces, that form when one soil mass moves over another and that have an area of at least 4 cm².

Solonetzic B horizon:The properties of this horizon are: 1) the ratio of exchangeable Ca to exchangeable Na is 10 or less (based on a laboratory analysis), 2) prismatic or columnar structure, 3) dark coatings on ped surfaces, and 4) hard to very hard consistence when dry.

Sphagnum:A major type of moss found in wetlands in forested and tundra regions of Canada.

Strongly calcareous:A CaCO3 equivalent % between 6-40.

Subangular blocky:The faces of aggregates are subrectangular, and the vertices are mostly oblique, or subrounded.

Terric layer:This is an unconsolidated mineral substratum not underlain by organic matter, or one continuous unconsolidated mineral layer (with ≤ 17% organic C) more than 30 cm thick in the middle or bottom tiers underlain by organic matter, within a depth of 1.6 m from the surface.

Texture:The solid material of soil is composed of different size fractions of particles: gravel (> 2 mm in diameter), sand (2 mm to 53x10-6 m), silt (53 to 2 x10-6 m), and clay (<2 x10-6 m). The texture is the particular mix of particle sizes found in any soil. In Canadian soils texture is almost entirely determined by the geomorphic processes responsible for depositing the original sediment.

Tillage erosion:The slow movement of soil particles in a net downhill direction by tillage implements. The cumulative effect of this process over time leads to the thinning (or truncation) of soils in upper slope positions and overthickening of soils in lower slope positions.

Translocation:The movement of soil components (e.g.. clay, iron, organic matter, solutes) from one position in the soil profile to another. Translocation can be in any direction in the profile, although translocation vertically downwards to greater depths in the soil is most important for soil classification.

Vertic horizon:A horizon affected by argillipedoturbation, which is the disruption and mixing of the horizon caused by shrinking and swelling of the clayey soil mass. It is characterized by the following: 1) irregular shaped, randomly oriented, intrusions of displaced materials within the solum. 2) vertical cracks, often containing sloughed-in surface materials. The disruption is strong enough to prevent the proper development of other horizons, or else severely change them.

von Post scale of Decomposition:

(text modified from Canadian System of Soil Classification, 3rd. Ed.)

In the field squeeze a sample of the organic material within your closed hand. Observe the color of the solution that is expressed between the fingers, the nature of the fibers, and the proportion of the original sample that remains in the hand. Ten classes are defined as follows:

1-Undecomposed; plant structure unaltered; yields only clear water colored light yellow-brown.2-Almost undecomposed; plant structure distinct; yields only clear water colored light yellow-brown.3-Very weakly decomposed; plant structure distinct; yields distinctly turbid brown water, no peat substance passes between the fingers, residue not mushy.4-Weakly decomposed; plant structure distinct; yields strongly turbid water, no peat substance escapes between the fingers, residue rather mushy.5-Moderately decomposed; plant structure clear but becoming indistinct; yields much turbid brown water, some peat escapes between the fingers, residue very mushy.6-Strongly decomposed; plant structure somewhat indistinct but clearer in the squeezed residue than in the undisturbed peat; about one-third of the peat escapes between the fingers, residue strongly mushy.7-Strongly decomposed; plant structure indistinct but recognizable; about half the peat escapes between the fingers.8-Very strongly decomposed; plant structure very indistinct; about two-thirds of the peat escapes between the fingers, residue almost entirely resistant remnants such as root fibers and wood.9-Almost completely decomposed; plant structure almost unrecognizable; nearly all the peat escapes between the fingers.10-Completely decomposed; plant structure unrecognizable; all the peat escapes between the fingers.

W:A W horizon is a layer of water which may occur in Gleysolic, Organic, or Cryosolic soils. Hydric layers in Organic soils are a kind of W layer, as is segregated ice formation in Cryosolic soils.

Weakly calcareous:A CaCO3 equivalent % between 1-6.

Weathering:The transformation of mineral particles in the soil. This can occur by physical weathering such as freeze-thaw processes and by various chemical weathering processes.

Wz:An ice layer which may occur in Gleysolic, Organic, or Cryosolic soils.